Why Georgia lawmakers almost always vote with their parties

WASHINGTON -- There are days here on Capitol Hill when it feels like the only issues that can unite all 16 of Georgia's lawmakers are the Savannah port and the state's water battles against Florida and Alabama.

We're generalizing, yes, but it does appear that the list of issues that can notch bipartisan support in Congress is shrinking by the year. New data from the Cook Political Report suggests why that's often the case.

Congress has become strikingly more polarized than it was even 20 years ago, according to the nonpartisan group. In 1997, 164 out of 435 House districts were considered "swing" districts, meaning that no one party dominated the region and bipartisan work was incentivized. That number is down 56 percent to just 72 such congressional seats today.

The group argues that gerrymandering is less of a factor than self-selection -- people moving to areas of the country where the prevailing local politics mirrors their own views.

Some Georgia-specific revelations from the group's latest report. Data nerds can read it here:

Doug Collins' 9th congressional district in Northeast Georgia is the third-most Republican in the country, favoring GOP candidates in presidential elections by 31 percentage points above the national average. Tom Graves' 14th District seat in the state's Northwest corner ranked 10th.

Conversely, John Lewis' 5th District seat, which encompasses much of the city of Atlanta, is the 14th most Democrat-friendly in the country. It favors Democrats by 34 percentage points above the national average.

The closest thing Georgia has to a swing district is in the 2nd district, which stretches South from Columbus and also includes Albany and Macon. Currently represented by Democrat Sanford Bishop, Democrats are favored there by 6 percentage points.

In our coverage of the 6th District special election we've talked plenty about how President Donald Trump barely won the district, which typically breaks hard for Republican presidential candidates. Cook rates it as the country's No. 8 Democratic-trending district. (Republicans are still favored there by 8 percentage points, but that's down from +14 before last November's election.) Rob Woodall's Gwinnett County-based 7th District also made the list.

The numbers help explain why some legislative accomplishments, including health care, have become so elusive in recent years.